ExxonMobil employees are testing a new process in western Wyoming that removes carbon dioxide and hydrogen sulfide from raw natural gas, a Houston-based account manager for the company said in Casper on Wednesday.
The technology promises to be a less expensive and more efficient way to capture and store carbon dioxide, thereby reducing greenhouse gas emissions, according to ExxonMobil. The recovered carbon dioxide could also be used in an oil industry method known as enhanced oil recovery, to renew old oil fields.
The manager, Tim Khayyal, said that the technology is called the Controlled Free Zone. Part of the CFZ process is cooling gas to about negative 50 degrees. At the company’s Shute Creek Treatment Facility in LaBarge, CFZ is in a commercial demonstration plant that will be able to process up to 14 million cubic feet of gas a day.
“It has been operating for more than a year during which time we have been conducting a wide variety of tests," said Patrick McGinn, an ExxonMobil spokesman, in an email.
At the Shute Creek facility, Exxon ships carbon dioxide by pipeline to partially depleted oil fields as part of enhanced oil recovery, whereby operators inject carbon dioxide at high pressures into oil fields, pushing oil to the surface and extending the lives of fields that would otherwise pump little oil.
“The point of the Free Zone test plant is to develop an alternative [carbon] capture technology that has the potential to increase CO2 EOR, not only in Wyoming but all over the United States,” said Glen Murrell, associate director of the Enhanced Oil Recovery Institute at the University of Wyoming.
In 2012, operators in Wyoming used carbon dioxide enhanced oil recovery to produce 7.2 million barrels of oil, or about 12.4 percent of the state’s total oil production, Murrell said.
That’s down from 2011, but that’s because there were issues flooding one of the oil fields with carbon dioxide. He declined to name which field had trouble.
“It’s a slight aberration in the overall trend, which is going up,” he said.
Enhanced oil recovery is expensive but has become possible in recent years, since the price of oil continues to increase. University of Wyoming economist Ben Cook said that when oil prices hit $140 a barrel, even more enhanced oil recovery projects will become available.
In addition to Shute Creek, carbon dioxide produced at ConocoPhillips’ natural gas plant at Lost Cabin is also piped into oil fields, Murrell said. The price of oil recently topped $100 a barrel.
While Shute Creek has a handful of customers – including the Salt Creek oil field in Natrona County, the Rangely project in Colorado, Beaver Creek outside Riverton, Monell-Patrick Draw near Rock Springs and Bairoil near Muddy Gap -- the only contract for Lost Cabin that has been publicly announced is to Denbury Resources Inc., which owns the Greencore Pipeline that winds through the oil fields of the Powder River Basin, Murrell said.